The Arrestin-like Protein palF Contributes to Growth, Sporulation, Spore Germination, Osmolarity, and Pathogenicity of .

is a dominant phytopathogen of grape white rot in China, significantly impacting grape yield and quality. Previous studies showed that the growth and pathogenicity of were affected by the environmental pH. Arrestin-like protein PalF plays a key role in mediating the activation of an intracellular-signaling cascade in response to alkaline ambient. However, it remains unclear whether palF affects the growth, development, and virulence of during the sensing of environmental pH changes. In this study, we identified a homologous gene of PalF/Rim8 in and constructed -silenced strains via RNA interference. -silenced strains exhibited impaired fungal growth at neutral/alkaline pH, accompanied by reduced pathogenicity compared to the wild-type (WT) and empty vector control (CK) strains. The distance between the hyphal branches was significantly increased in the -silenced strains. Additionally, -silenced strains showed increased sensitivity to NaCl, HO, and Congo red, and decreased sensitive to CaSO. RT-qPCR analysis demonstrated that the expression level of genes related to pectinase and cellulase were significantly down-regulated in -silenced strains compared to WT and CK strains. Moreover, the expression of , was directly or indirectly affected by silencing . Additionally, the expression of genes related to plant cell wall-degrading enzymes, which are key virulence factors for plant pathogenic fungi, was regulated by . Our results indicate the important roles of in growth, osmotolerance, and pathogenicity in .